The present invention relates to a mount construction for a bearing seal that may be incorporated into a computer device, audio device, and the like. More specifically, the present invention relates to the mount construction for the bearing seal in which the bearing seal may be mounted on the bearing for sealing it, wherein the bearing seal, having a reinforcing ring and an elastic element having a lip and disposed on one side of the reinforcing ring, is inserted into the bearing and mounted on it by using a ring element or diameter-squeezing ring that may prevent the before mentioned lip from being wound between the reinforcing ring and the bearing.
In a conventional bearing seal that may be mounted on a bearing for preventing the escape of the lubricating oil from the bearing and for protecting the bearing against the entry of any dust or water from the outside, the bearing seal includes an engaging portion that is adapted to engage the fitting groove formed on the bearing when the bearing seal is mounted on the bearing. The engaging portion is formed from a flexible material so that it can provide a good engaging ability. Usually, this mounting is performed by causing the engaging portion to become greatly greatly and pressing it into the fitting groove on the bearing.
For the conventional mount construction as described above, wherein the bearing seal may be mounted on the bearing by pressing its engaging portion into the fitting groove, it is required that the engaging portion should have a volume that is large enough to make it flexible, and allow it to become greatly deformed. This mount construction has several problems, however. One problem is that, when the bearing seal having a large volume engaging portion is mounted on the bearing, the engaging portion tends to become excessively elastic, which imposes a limitation on the ability of the engaging portion to prevent the bearing seal from slipping out of the bearing. Another problem is that the ability of the engaging portion to engage the fitting groove may be reduced because it becomes greatly deformed.
In recent years, an improved mount construction for bearing seal has been developed to address the above problems (for example, Japanese Utility Model Registration Application now published under No. H6 (1994)-51555). This mount construction provides an improvement over the prior one. It is disclosed that the bearing seal includes a reinforcing ring and an elastic element having a lip and disposed on one side of the reinforcing ring, wherein the lip is formed to project radially and outwardly beyond the outer peripheral edge of the reinforcing ring. The bearing seal may be mounted on the bearing by placing it into the bearing from the side of the elastic element, and then by causing the lip to be deformed so that it can be wound around the outer peripheral edge of reinforcing ring and into the fitting groove formed on the bearing.
According to such method as described above, wherein the bearing seal may be secured to the bearing by causing the lip to be wound around the outer peripheral edge of reinforcing ring, the lip has the form of an elastic element made of rubber (which is hereinafter referred to as xe2x80x9crubber lipxe2x80x9d), and the said rubber lip is held between the inner peripheral surface of the outer race of the bearing and the outer peripheral surface of the reinforcing ring. Accordingly, the rubber lip may be allowed to deform itself by forcing it to engage both the inner peripheral surface of the outer race of the bearing and the outer peripheral surface of the reinforcing ring. Thus, high dimensional precision is required for accurately placing the bearing seal in the bearing. Otherwise, the rubber lip might not be wound around the outer peripheral edge of the reinforcing ring uniformly, so that the mounting would be imperfect.
For the above reason, each of the individual mechanical component parts of the bearing, as well as each of the components of the bearing seal being mounted on the bearing, must have high dimensional precision when it is fabricated, in order to permit the rubber lip to be held uniformly over the outer and inner peripheral surfaces of the bearing, and to permit the bearing seal to be positioned accurately on the bearing.
When the rubber lip is wound around the outer peripheral edge of reinforcing ring as described above, the rubber lip is greatly deformed so that it can surround the outer periphery of the reinforcing ring. Thus, it may exert a strong pressure upon the reinforcing ring, which must have high mechanical strength and spring action to resist such pressure.
When the bearing seal is mounted on the bearing and the rubber lip is wound around the outer peripheral edge of reinforcing ring, the rubber lip may have some part of its tip appearing and exposed beyond the end of the bearing. Thus, the bearing must have an extra space to accommodate such part of the tip therein.
In order to solve the problems of the prior art described above, the present invention provides a mount construction for bearing seal that allows it to accept the total volume of the lip of the bearing seal in the fitting groove formed on the outer race of bearing, so that the lip of the bearing seal is engaged in the fitting groove, whereby the bearing seal can be mounted on the bearing firmly and securely. Thus, the strength of sealing and engaging is prevented from being lost, after the bearing seal is mounted on the bearing, and a stable sealing function for the bearing is obtained. Also, according to the present invention, the bearing seal is mounted on the bearing easily and securely by using a ring element or diameter-squeezing ring that allows for mounting the bearing seal on the bearing while accepting the total volume of the lip of the bearing seal in the fitting groove formed on the outer race of bearing, thereby engaging the lip of the bearing seal in the fitting groove.
More specifically, one aspect of the present invention provides a mount construction for bearing seal mounting a bearing seal on a bearing by engaging the bearing seal with a fitting groove formed around an inner periphery of an outer race of the bearing, thereby sealing the inside of the bearing from the outside. A bearing seal includes a reinforcing ring and an elastic element disposed on one side of the reinforcing ring and having a lip formed to project radially and outwardly beyond the outer peripheral edge of the reinforcing ring. The bearing seal is pressed into a ring element from the side on which the reinforcing ring is located, and mounted inside the ring element, wherein the ring element has its inner diameter that is greater than the outer diameter of the reinforcing ring and is smaller than the bore diameter of the outer race of the bearing. When the bearing seal is mounted in the ring element, the lip is bent toward the direction away from the outer peripheral edge of the reinforcing ring on the side of the bearing seal at which the elastic element is located. Then, the ring element is made to engage the bore of the outer race of bearing while directing the elastic element of the bearing seal toward the inside of bearing. In this state, the bearing seal is then pushed out of the ring element and into the bore of the outer race of the bearing with the lip thus bent toward the direction away from the outer peripheral edge of the reinforcing ring on the side of the bearing seal at which the elastic element is located, directing the elastic element of the bearing seal toward the inside of the bearing. This may cause the fitting groove on the outer race of bearing to accept the lip, whereby the lip is engaged in the fitting groove, and the mounting may thus be completed.
Another aspect of the present invention provides a mount construction for a bearing seal mounting a bearing seal on a bearing by engaging the bearing seal with a fitting groove formed around an inner periphery of an outer race of the bearing, thereby sealing the inside of the bearing off from the outside. The bearing seal includes a reinforcing ring and an elastic element disposed on one side of the reinforcing ring and having a lip formed to project radially and outwardly beyond the outer peripheral edge of the reinforcing ring. A diameter-squeezing ring is mounted around the bearing seal. The diameter-squeezing ring has its inner diameter, as it is squeezed, greater than the outer diameter of the reinforcing ring and smaller than the bore diameter of the outer race of the bearing. When the diameter-squeezing ring is mounted around the bearing seal, the lip is bent toward the direction away from the outer peripheral edge of the reinforcing ring on the side of the bearing seal at which the elastic element is located. Then, the diameter-squeezing ring is made to engage the bore of the outer bearing race while directing the elastic element of the bearing seal toward the inside of bearing. In this state, the bearing seal is then pushed out of the diameter-squeezing ring and into the bore of the outer race of bearing with the lip thus bent toward the direction away from the outer peripheral edge of the reinforcing ring on the side of the bearing seal at which the elastic element is located, directing the elastic element of the bearing seal toward the inside of the bearing. This may cause the fitting groove on the outer race of bearing to accept the lip, whereby the lip is engaged in the fitting grove, and the mounting is thus be completed.
According to each of the before described aspects of the present invention, the elastic element may be made of any type of rubber material that has a hardness of 55 to 90xc2x0 Hs. The rubber material may be molded into the shape of the elastic element, which may then be heated again.
Any type of bearing seal that includes the reinforcing ring and the elastic ring disposed on one side of the reinforcing ring and having the lip formed to project radially and outwardly beyond the outer peripheral edge of the reinforcing ring as described above may be employed. The bearing seal may be obtained by using various methods. For example, the stamping method may be used. In this case, a thin plate having any suitable rubber material on one side thereof is stamped into the shape of the bearing seal. Alternatively, the pre-molding method may also be used. In this case, an elastic element may be obtained by preliminary molding so that it can have the lip, and then this elastic element may be stamped together with the reinforcing ring. Other methods may be employed, and the choice of any of the methods may be determined, depending on the particular needs. It should be understood that the form of the lip is not limited to the shapes shown and described, and the lip may take other different forms.
The reinforcing ring is provided to supplement the mechanical strength of the bearing seal. Thus, the reinforcing ring may be formed from any metal or alloy plates such as steel, stainless, aluminum and the like or any hard plastics, which are all known in the art. Which of those materials should be used may be determined, depending on the performance required for the bearing seal, the particular usages thereof and other needs.
The function of the elastic element having the lip described above is to prevent the bearing seal from slipping out of the bearing on which it is mounted, and to provide the property of sealing the bearing tightly and securely. For example, such rubber materials may include synthetic rubber materials, such as nitrile rubber (NBR), fluororubber (FKM), acryl rubber (ACM), styrene rubber (SBR), polychloroprene rubber (CR), butadiene rubber (BR), isobutylene-isoprene rubber (IIR), and the like. The choice may be made as appropriate, depending on the performance required for the bearing on which the bearing seal is mounted.
The rubber materials from which the elastic element may be made should preferably have the hardness of 55 to 90xc2x0 Hs. After any rubber material is molded into the shape of the elastic element, it may be processed to provide the higher hardness by heating it again (secondary vulcanization). Although the hardness of 55 to 90xc2x0 Hs may be comparatively high, the rubber material should preferably have such hardness in that the elastic element made of such rubber material can prevent the bearing seal from slipping out of the bearing, and can seal the bearing more tightly and securely.
As described, the ring element may be used to cause the lip on the elastic element to be bent toward the direction away from the outer peripheral edge of the reinforcing ring on the side of the bearing seal at which the elastic element is disposed, before the bearing seal is pushed into the bearing and secured to the bearing. Specifically, as the bearing seal is pressed into the ring element from the side of the reinforcing ring, the reinforcing ring may act upon the lip so that it can be drawn into the ring element. Then, the ring element may cause the lip to be bent in the manner as described above. Thus, the bearing seal may be mounted on the ring element simply by pressing the bearing seal into the ring element from the side of the reinforcing ring.
As described, the ring element has its inner diameter greater than the outer diameter of the reinforcing ring and smaller than the bore diameter of the outer race of the bearing. This dimensional relationship may be expressed as follows.
bore diameter of the outer race xe2x89xa7 inner diameter of the ring element  greater than  outer diameter of the reinforcing ring
Given the above dimensional relationship, the bearing seal can be mounted on the bearing securely, and this mounting can be performed smoothly and properly.
Naturally, the inner diameter of the ring element should be greater than the outer diameter of the reinforcing ring, since the reinforcing ring must be inserted through the ring element.
In the prior art method in which the lip is made to engage the fitting groove on the outer race of the bearing without using the ring element, or more specifically, in the prior art method in which the bearing seal is pressed into the bearing with the lip being directed toward the bearing, the bearing seal may be inserted into the bearing by causing the reinforcing ring to push the lip into the bearing and by then forcing the lip to make sliding contact against the inner peripheral surface of the outer race of the bearing. Some stress may remain in the area of the lip that makes sliding contact against the inner peripheral surface of the outer race, with the lip being held between the peripheral edge of the reinforcing ring and the inner peripheral surface of the outer race. If any stress remains, the lip cannot totally enter the fitting groove when the lip is made to engage the fitting groove. It is noticed that if the gap between the peripheral surface of the reinforcing ring and the bore diameter of the outer race of bearing is smaller than the thickness of the lip, the lip would not be able to overcome the sliding pressure, which might lead to the breakage of the lip. Conversely, if the gap is greater, the lip would not be held between the peripheral surface of the reinforcing ring and the inner peripheral surface of the outer race of the bearing. Thus, the mounting could not be achieved.
In contrast, when the ring element is used, the outer diameter of the elastic element 6 as shown in FIG. 8 may be smaller than the bore diameter D2 of the outer race 2a of the bearing 3, as is the case with the inner diameter D3 of the ring element 7 described above. When the lip is placed in its bent state with its tip being directed toward the inside of the bearing, the bearing seal can be slid into the bearing, beginning with the elastic element 6 followed by the reinforcing ring 5. Thus, the bearing seal can be pushed into the bearing smoothly, without having to exert any excessive pressure load upon the bearing seal.
It should be noted that the possibility of the bearing seal slipping out of the bearing may depend largely upon the parameters for the bore diameter of the outer race of the bearing and the outer diameter of the reinforcing ring, that is, how much clearance can be provided between those two diameters. If the clearance is smaller, the bearing seal can be secured to the bearing, and there will be less risk of the bearing seal slipping out of the bearing. Conversely, if the clearance is larger, the lip might become deformed more largely when it engages the fitting groove, and the risk of the bearing seal slipping out of the bearing will be increased accordingly. By considering the above, the clearance should be determined as appropriate, depending upon the particular type of the bearing used, and the performance required for the particular bearing type.
The diameter-squeezing ring that has been mentioned earlier serves the same purpose as the ring element just described above. The diameter-squeezing ring may take the form of a collet chuck or a C-shape spring pin. The diameter-squeezing ring may have any form, as long as it may be mounted around the bearing seal by gradually reducing its diameter, and it can maintain the lip to be bent toward the direction away from the peripheral edge of the reinforcing ring on the side of the elastic element.
For the same reason as for the ring element described above, naturally, the inner diameter of the diameter-squeezing ring as it is squeezed should be larger than the outer diameter of the reinforcing ring, since the diameter-squeezing ring must be mounted around the reinforcing ring.
Like the ring element, the inner diameter of the diameter-squeezing ring as it is squeezed may be larger than the outer diameter of the reinforcing ring, and may be smaller than the bore diameter of the outer race of the bearing. This dimensional relationship may be expressed as follows.
bore diameter of the outer race xe2x89xa7 inner diameter of the diameter-squeezing ring as it is squeezed  greater than  outer diameter of the reinforcing ring
Given the above dimensional relationship, the bearing seal can be mounted on the bearing securely, and this mounting can be performed smoothly and properly.
Any suitable pushing tool may be used when the bearing seal is pushed out of the ring element.